You could do it the backyard way Take a few small sheet metal screws and screw them into the seal, take some diagonal wire cutters to pry up on the screws and pull the seal out. Drywall screws work. Be careful not to scratch the case. Install the new seal being careful of the flats on the shaft tearing it, tap it in with a 9/16 deep socket.
Make sure no one has installed two seals, if so remove both.